Natural gas is the second-largest primary energy source for generating electricity in the United States and the world. Natural gas power plants have the advantage of modest capital costs, high fuel efficiency, operating flexibility, rapid deployment, and low greenhouse gas and pollutant emissions. New natural gas power plants are growing at an annual rate of 2% worldwide, faster than any other type, and their global share of electricity production should increase from 20.1% in 2006 to 22.3% in 2030. [1]

A power plant fueled by natural gas has many of the same components as a coal-fired integrated gasification combined cycle (IGCC) plant, except that the natural gas plant needs neither a gasifier to convert coal to syngas (a gas composed of carbon monoxide and hydrogen) for the combustion turbines nor gas filters to mitigate sulfur dioxide (SO2) or nitrogen oxide (NOx) emissions. This is because refineries, during the processing of natural gas, remove most of the sulfur and nitrogen impurities that generate SO2 and NOx. A basic natural gas power plant contains only a combustor, a combustion turbine, and a generator. A higher-efficiency, “combined-cycle” plant adds a heat recovery unit, a steam turbine, a condenser, and another generator.

Because of their simplicity, natural gas power plants are relatively inexpensive and rapid to construct, efficient to operate, and easy to maintain. Construction of a power plant that generates 1000 megawatts (MW) may take as little as 2 years from start to finish. Most of the plants in the United States use combined-cycle combustion and steam turbines and attain fuel efficiencies that average 39%, [2] and plants currently under construction should approach 60% efficiency. [3] The economics of such plants, however, fluctuate with the price of natural gas, which is usually several times more expensive than coal.